April 22, Tuesday. The last Alvin dive yesterday had its share of close encounters with seamonsters, to be posted here and now before the ship arrives in Gulfport at 2 pm and mundane reality sets in. Here we go! Alvin is working away, recovering Ian’s camera from the shores of Dead Crab Mud Volcano, when the alien invasion starts, 831 m deep down.
These little translucent aliens are dancing around the sub and have their pictures taken. They look like transparent swimming crabs with leg appendages and some sort of quickly beating swimming tail studded with fast-moving cilia, and all this capped by a barrel-like transparent tube. A bizarre larva perhaps? Whatever they are, they seem to be attracted by the Alvin lights. Anyway – next comes THIS.
A true Primadonna of a jellyfish cruises up and down in full view of the Alvin cameras, and swims with powerful pumping motions as it ejects water ventrally (I assume) by contracting its body. It is doing loops and turning around so that we can admire its ventral opening, or maw. By the looks of it, I would not be surprised if the tentacles sting.
Such life forms can only be truly observed in their native habitat. Imagine catching this jelly in a net… only a reddish blob of jam would survive the trip to the surface. The deep sea harbors many biological secrets and will without any doubt keep many of them.
For the next picture, we hope you have already eaten your lunch. A black eel is hanging almost vertically in the water and carrying something in its mouth that looks like a high degraded fish carcass, perhaps found in Dead Crab Lake. The eel tries several times to gulp it down, but the carcass is hard to handle; finally the eel swims away, its lunch still dangling from its mouth. The movie version is something!
Last but not least, the very place itself – Dead Crab Mud Volcano – is alive. The mud volcano is active and sends fingers of mud crawling over the surrounding deep-sea floor.
Alvin follows the fresh mudflow from shore to the center of the lake and finds a fresh mud volcano crater spewing mud and bubbles. Dead Crab Mud Volcano is undergoing one of its episodic eruptions of gas and fluidized mud. Over time in the last four years, these eruptions must have filled up the lake with mud and pushed its clear brine out.
Over the last few days, since dive 4694, the mud level must have been rising; Ian’s camera was left on the lake shore on solid ground stained black by reducing brine flow, and is now sitting ankle deep in light-grey mud. This mud volcano is very much active and demonstrates seafloor geology in action!
The old coring holes behind the VTLC camera are still visible, but soon they will be swallowed by the rising mud. A timely rescue for the camera … it turns out to have recorded good footage for three full days. The dive time is almost up anyway and it is time to grab the camera and run! Nobody wants to share the fate of this fish in the mud volcano who took research a little too far. The gulper eel will be waiting…